Method of instrumenting a component

ABSTRACT

A method of instrumenting a first component ( 210 ) for use in a combustion turbine engine ( 10 ) wherein the first component ( 210 ) has a surface contacted by a second component during operation of the combustion turbine engine ( 10 ). The method may include depositing an insulating layer ( 260 ) on the surface of the first component ( 210 ) and depositing a first conductive lead ( 232, 254 ) on the insulating layer ( 260 ). A piezoelectric material ( 230 ) may be deposited in electrical communication with the first conductive lead ( 232, 254 ) and a second conductive lead ( 236, 256 ) may be deposited in electrical communication with the piezoelectric material ( 230 ) and be insulated from the first conductive lead ( 232, 254 ) to form a sensor ( 50 ) for detecting pressure exerted on the surface of the first component ( 210 ) during operation of the combustion turbine engine ( 10 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.11/122,566 filed May 5, 2005, which is a continuation-in-part ofapplication Ser. No. 11/018,816 filed Dec. 20, 2004, which claims thebenefit of U.S. Provisional Patent Application No. 60/581,662 filed Jun.21, 2004 and which is a continuation-in-part of application Ser. No.10/252,236 filed Sep. 23, 2002, U.S. Pat. No. 6,838,157, all of whichare specifically incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to monitoring operatingenvironments and in particular to embedded sensors for sensing operatingparameters of components within an operating environment such as a gasturbine engine.

BACKGROUND OF THE INVENTION

Despite the extreme sophistication of gas turbine engines, such asturbines for generating electrical power or aircraft engines forcommercial and military use, designers and operators have deficientinformation with respect to the operational relationship of certainengine components. This is due at least in part to harsh operatingconditions and close tolerances between certain components, which oftenprevent using traditional sensors for collecting accurate information ofcritical engine components.

Some components within a turbine engine are assembled using a slip fitsuch as a dovetail, fir tree, T-slot and others. Turbine components suchas vanes and ring segments may slide into grooves and be held in placewith air pressure used to cool the components during operation. Turbineblades may fit into a turbine disk and be held in place by centrifugalforce during operation. Nonetheless, turbine vanes, blades and othercomponents tend to vibrate during operation due to air flowing throughthe turbine. This flow induced vibration leads to wear at contactsurfaces causing inefficient turbine operation and may lead to criticalcomponent failure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of an exemplary combustion turbine withwhich embodiments of the invention may be used and an exemplarymonitoring and control system for collecting and analyzing componentdata from the combustion turbine.

FIG. 2 a perspective view of an exemplary combustion turbine vaneequipped with an exemplary embodiment of the present invention.

FIG. 3 is a schematic view of a vane of FIG. 2.

FIG. 4 is a schematic cross section of the compressor of FIG. 1.

FIG. 5 is a perspective partial view of an exemplary embodiment of asmart component combustion in accordance with aspects of the invention.

FIG. 6A is a schematic view of an exemplary embodiment of the componentof FIG. 5.

FIG. 6B is a schematic view of an exemplary embodiment of the componentof FIG. 5.

FIG. 6C is a schematic view of an exemplary embodiment of the componentof FIG. 5.

FIG. 7 is an exemplary embodiment of a heat flux sensor.

FIGS. 8 and 9 illustrate an exemplary embodiment of a strain gauge and acrack propagating to different lengths.

FIG. 10 is a partial perspective view of a component having a sensorembedded within a layer of thermal barrier coating material disposedover a substrate material.

FIG. 11 is a partial cross-sectional view of a component having aplurality of sensors embedded at varying depths below a surface of thecomponent.

FIG. 12 is a process diagram illustrating steps in a method ofmanufacturing the component of FIG. 11.

FIG. 13 is a plan view of a portion of an exemplary turbine.

FIG. 14 is an exemplary ring segment of a combustion turbine.

FIG. 15 is an exemplary embodiment of a load cell.

FIG. 16 is an exemplary embodiment of an accelerometer; and

FIG. 17 is a cross section of the load cell of FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary combustion turbine 10 such as a gasturbine used for generating electricity as will be recognized by thoseskilled in the art. Embodiments of the invention may be used withcombustion turbine 10 or in numerous other operating environments. Forexample, embodiments may be used in aircraft engines for evaluatingoperation parameters and relationships of vibrating component.

Combustion turbine 10 may include a compressor 12, at least onecombustor 14 (broken away) and a turbine 16. Compressor 12, combustor 14and turbine 16 are sometimes referred to collectively as a gas turbineengine. Turbine 16 includes a plurality of rotating blades 18, securedto a rotatable central shaft 20. A plurality of stationary vanes 22 arepositioned between blades 18, with vanes 22 being dimensioned andconfigured to guide air over blades 18. Blades 18 and vanes 22 willtypically be made from nickel-cobalt, and may be coated with a thermalbarrier coating 26, such as yttria-stabilized zirconia. Similarly,compressor 12 includes a plurality of rotating blades 19 positionedbetween respective vanes 23.

Embodiments of the invention may be used to acquire diagnosticinformation pertaining to blades 18 and vanes 22 as well as othercomponents subject to flow induced vibration including combustor 14,fuel nozzles, “swirlers”, cross flame tubes, ring segments, isolationrings, thermocouples, seals and other components recognized by thoseskilled in the art.

In use, air is drawn in through compressor 12, where it is compressedand driven towards combustor 14. Combustor 14 mixes the air with fueland ignites it thereby forming a working gas. This working gas willtypically be above 1300° C. This gas expands through turbine 16, beingguided across blades 18 by vanes 22. As the gas passes through turbine16, it rotates blades 18 and shaft 20, thereby transmitting usablemechanical work through shaft 20. Combustion turbine 10 may also includea cooling system (not shown), dimensioned and configured to supply acoolant, for example steam or compressed air, to blades 18 and vanes 22.

The environment wherein blades 18 and vanes 22 operate is subject tohigh operating temperatures and is particularly harsh, which may resultin serious deterioration of blades 18 and vanes 22. This is especiallylikely if the thermal barrier coating 26 should spall or otherwisedeteriorate. Embodiments of the invention are advantageous because theyallow components to be configured for transmitting data indicative ofoperating parameters associated with components during operation ofcombustion turbine 10. Blades 18, 19, vanes 22, 23, and coatings 26, forexample, may be configured for transmitting data indicative of operatingcharacteristics of those components. This date may be collected andanalyzed in real time and used for various purposes such as to directlymonitor those operating characteristics during operation, developpredictive maintenance schedules, control operating parameters, validatedesign models and minimize resonance of combustion turbine 10components.

FIG. 1 also illustrates a schematic of an exemplary monitoring andcontrol system 30 that may include an antenna 32, a receiver 33, aprocessor or CPU 34, a database 36 and a display 38. Processor 34,database 36 and display 38 may be conventional components and antenna 32and receiver 33 may have performance specifications that are a functionof various embodiments of the invention. For example, antenna 32 andreceiver 33 may be selected for receiving wireless telemetry datatransmitted from a plurality of transmitters deployed in variouslocations throughout combustion turbine 10 as more fully describedbelow.

Embodiments of the present invention allow for a plurality of sensors tobe embedded within the respective coatings of a plurality of componentswithin combustion turbine 10. Alternate embodiments allow for thesensors to be surface mounted or deposited to components, especiallythose contained in areas where components do not require a barriercoating such as the compressor 12. Exemplary embodiments of sensors maybe used to provide data to system 30 with respect to the load exerted onan area of interest of a component, such as an area contacting anothercomponent during operation. Data may also be transmitted with respect tothe acceleration of a component and/or properties of a component'scoating as well as other component or coating specific information.

It will be appreciated that aspects of the invention allow for varioussensor configurations to be embedded within a barrier coating such as abarrier coating 26 of blades 18 or vanes 22 as well as other componentsof turbine 16. U.S. Pat. No. 6,838,157, which is specificallyincorporated herein by reference, describes various embodiments ofmethods for instrumenting gas turbine components that may be utilizedwith aspects of the present invention. This patent discloses variousmethods of forming trenches in a barrier coating, forming a sensor inthe coating and depositing a backfill material in the trench over thecoating. Alternate embodiments allow for sensor configurations to beembedded during the formation of a functional coating such as a thermalbarrier coating or wear coating, for example. Exemplary sensorconfigurations may be deposited on component surfaces as well.

U.S. Pat. No. 6,576,861, which is specifically incorporated herein byreference, discloses an exemplary direct write apparatus and processrecognized in the art that may be used to deposit embodiments of sensorsand sensor connectors with transmitters in accordance with aspects ofthe present invention. In this respect, the apparatus and processesdisclosed therein may be used for the patterning of fine sensor and/orconnector features of between about 100 microns and 500 microns.Multilayer electrical circuits and sensors may be formed by depositingfeatures using conductive materials, resistive materials, dielectricmaterials, insulative materials and other application specificmaterials. It will be appreciated that other methods may be used todeposit multilayer electrical circuits and sensors in accordance withaspects of the invention. For example, thermal spraying, vapordeposition, laser sintering and curing deposits of material sprayed atlower temperatures may be used as well as other suitable techniquesrecognized by those skilled in the art.

Embodiments of the invention allow for a single sensor 50 or a pluralityof sensors 50 to be deployed in numerous places within combustionturbine 10. In an embodiment, sensor 50 may be formed of a piezoelectricand/or piezoresistive material and deposited using the direct writeapparatus. Piezoelectric and piezoresistive materials may be referred tocollectively as piezo-material. Exemplary piezoelectric materials mayinclude alpha-quartz, barium titanate, lead zirconium titanate, lithiumniobate and others. Alternate embodiments allow for depositingpiezoresistive materials to form exemplary sensors 50 such as a loadcell or accelerometer. Sensor 50 may be used for monitoringcomponent-specific or coating-specific conditions as well as collectingother data with respect to the operation or performance of combustionturbine 10. For example, FIG. 1 illustrates that one or more sensors 50may be embedded within respective barrier coatings 26 of one or moreblades 18 of turbine 16. It will be appreciated that sensors 50 may beembedded within barrier coatings, wear coatings and surfaces of otherrespective components with turbine 16 for which component-specificand/or coating-specific data is to be acquired.

FIG. 2 illustrates a pair of vanes 23 removed from compressor 12 withone vane having a sensor 50 mounted or connected with vane 23 fordetecting a condition of vane 23. A connector 52 may be provided as ameans for routing a data signal from sensor 50 to a transmitter 54configured for wirelessly transmitting the data signal to a transceiver56. Connector 52 may be one or a plurality of electrical leads forconducting a signal from sensor 50 to a surface mounted transmitter 54.Alternate embodiments allow for various types of connectors 52 to beused as a means for routing a data signal from sensor 50 to transmitter54, depending on the specific application. For example, one or aplurality of fiber optic connectors may be used for routing a signalusing single or varying wavelengths of light.

Embodiments allow for transmitters 54 to be multi-channel and havevarious specifications depending on their location within a casing ofcombustion turbine 10. Transmitters 54 may be configured to functionwithin the compressor 12 casing subject to operating temperatures ofbetween about 80° C. to 120° C. They may also be configured to functionwithin the turbine 12 casing subject to operating temperatures ofbetween about 300° C. to 350° C. or higher, and be resistant tooxidative exposure.

FIG. 3 illustrates a schematic plan view of compressor vane 23 havingsensor 50 connected therewith and connector 52 connecting sensor 50 withtransmitter 54. A power source 51 may be provided, such as anappropriately sized battery for powering transmitter 54. In alternateembodiments transmitter 54 may be located remotely from vane 23 andpowered from an external power source. Transmitter 54 may receivesignals from sensor 50 via connector 52 that are subsequently wirelesslytransmitted to transceiver 56. Transceiver 56 may be mounted on hub 58or on a surface external to compressor 12 such as the exemplarylocations shown in FIG. 1. Transceiver 56 may be mounted in variouslocations provided it is within sufficient proximity to transmitter 54to receive a wireless data transmission, such as an RF signal fromtransmitter 54. Transceiver 56 may transmit the RF signal to antenna 32of system 30 where the signal may be processed for monitoring thecondition of compressor vane 23.

With respect to FIGS. 2 and 3, one or more sensors 50 may be connectedwith one or more compressor vanes 23 by fabricating sensor 50 directlyonto a surface of vane 23. Connector 52 may be deposited directly onto asurface of vane 23. In alternate embodiments a trench or recess may beformed within a surface of vane 23 that is sized for receiving adeposited sensor 50 and connector 52. Sensor 50 and connector 52 may bedeposited within the recess and protected by depositing a coating ofsuitable material onto a surface of vane 23 over sensor 50 and connector52. In other alternate embodiments a coating may be deposited onto asurface of vane 23, a trench may be formed within the coating and sensor50 and connector 52 may be deposited within the trench. A protectivecoating may be deposited over sensor 50 and/or connector 52.

Connector 52 may extend from sensor 50 to a termination location, suchas the peripheral edge of vane 23 so that a distal end 53 of connector52 is exposed for connection to transmitter 54. Sensor 50 and connector52 may be positioned on vane 23 to minimize any adverse affect on theaerodynamics of vane 23.

In an embodiment, one or more sensors 50, such as strain gauges orthermocouples, for example, may be deposited on one or more turbine orcompressor blades 18, 19. FIG. 4 illustrates an embodiment with respectto compressor 12. A connector 52 may be deposited to connect each sensor50 to one or more transmitters 54 connected with blade 18, 19. It willbe appreciated that exemplary embodiments allow for a plurality ofsensors 50 to be connected with a single transmitter 54 via respectiveconnectors 52. For example, a sensor 50 may be deposited on each of aplurality of blades 18, 19. A connector 52 may be deposited to route asignal from each sensor 50 to a single transmitter 54.

Transmitter 54 and a rotating antenna 55 may be mounted proximate theroot of blade 18, 19. Connector 52 may be routed from sensor 50 aft tothe root of blade 18, 19 to connect sensor 50 with rotating antenna 55,which may in turn be connected with transmitter 54 via a connector 52 a.A stationary antenna 57 may be installed on a turbine or compressor vane22, 23 aft of the root of respective blade 18, 19. A lead wire 57 a maybe routed from stationary antenna 57 out of compressor 12 or turbine 16to broadcast a signal to system 30. In exemplary embodiments, such asthat shown in FIG. 4, power may be generated through induction duringoperation of compressor 12 as will be appreciated by those skilled inthe art. In this arrangement, transmitter 54 may transmit data tostationary antenna 57 via rotating antenna 55 and power may be suppliedfrom stationary antenna 57 to transmitter 54.

It will be appreciated by those skilled in the art that one or moresensors 50 may be mounted to, such as by a spray deposition, eachcompressor blade 19 within a row of blades 19 mounted on a disk withincompressor 12. A respective connector 52 may connect each sensor 50 to arespective transmitter 54 mounted proximate the root of each blade 19within the row. Rotating antenna 55 may encircle the disk proximate theroot of each blade 19 and be connected with each transmitter 54 via arespective connector 52 a. One or more stationary antennas 57 may beinstalled on a compressor vane 23 aft of the row of compressor blades19, or in another location, such as a compressor hub sufficientlyproximate to rotating antenna 55 for signal broadcasting and receiving.Stationary antenna 57 may also encircle the row of blades 19. Rows ofblades 18 in turbine 16 may be similarly configured.

FIG. 5 illustrates a partial view of a component, such as a vane 22 fromturbine 16 having a barrier coating 26 deposited thereon. Sensor 50 andconnector 52 may be embedded beneath an upper surface of barrier coating26. Connector 52 may have a distal end 53 that is exposed at atermination location, such as proximate a peripheral edge 59 of vane 22for connection with transmitter 54. In an embodiment transmitter 54 maybe surface mounted to vane 22 or embedded within coating 26 proximateperipheral edge 59. Alternate embodiments allow for transmitter 54 to belocated elsewhere such as on a platform (not shown) to which vane 22 isconnected or in a cooling flow channel, for example, as will berecognized by those skilled in the art.

FIG. 6A illustrates a schematic plan view of a blade 18 having anexemplary sensor 50 connected therewith and connector 52 connectingsensor 50 with transmitter 54. Transmitter 54 may be powered throughinduction generated within turbine 16 during operation that will beappreciated by those skilled in the art. FIGS. 6A, 6B and 6C illustrateexemplary embodiments of a turbine blade 18 having transmitter 54 placedin various locations. In FIGS. 6A and 6B transmitter 54 may be mountedto blade 18 and FIG. 6C illustrates that transmitter 54 may be locatedremote from blade 18. For example, transmitter 54 may be locatedremotely from blade 18 such as within a disk (not shown) to which aplurality of blades 18 is attached. In this respect, transmitter 54 maybe maintained in a cooler location outside the hot gas path, which mayincrease the transmitter's useful life. Locating transmitter 54 remotefrom blade 18 allows for using an external power source for poweringtransmitter 54 rather than using a battery or induction.

A power supply may also be attached to sensor 50 to provide additionalfunctionality to the sensor. This additional functionality could includemechanical actuation as a result of feedback to the sensor 50 output.Such an integrated system may be applicable for components, such as ringsegments for real-time gap control.

The exemplary embodiments of compressor vane 23 and turbine blade 18illustrated in FIGS. 3-6A, 6B and 6C configured with self-containedsensors 50 and connectors 52 are advantageous in that they may beprefabricated for installation in combustion turbine 10 by a fieldtechnician. Embodiments allow for a distal end 53 of connectors 52 to beexposed at a termination location. This location may be proximate aperipheral edge of a component or other location. This allows a fieldtechnician to quickly and easily connect connector 52 to a transmitter54 regardless of its location.

Providing components of combustion turbine 10, such as vanes 23 and/orblades 18 with pre-installed sensors 50 and connectors 52 is asignificant advantage over previous techniques for installing suchcomponents in the field, which typically required an extensive array ofwires to be routed within combustion turbine 16. Providing componentswith pre-installed sensors 50 and connectors 52 allows for monitoringthe condition of those specific components during operation ofcombustion turbine 10.

Embodiments of the invention allow for sensor 50 to be configured toperform a wide range of functions. For example, sensor 50 may beconfigured to detect wear of a single component or between twocomponents, measure heat flux across a component's coating, detectspalling of a coating, measure strain across an area of a component ordetermine crack formation within a component or coating. U.S. patentapplication having application Ser. No. 11/018,816 discloses embodimentsof a system that generally involves monitoring the wear of a componentthat may be configured in accordance with embodiments of the presentinvention.

Wear sensors 50 may be configured as embedded electrical circuits in acontact surface of a component, such as a tip of blade 18 and thecircuit may be monitored by monitoring system 30 for indications ofwear. By positioning a circuit at the wear limit, or at prescribeddepths from the component's surface, the condition of the surface may becontinuously monitored and system 30 may provide an operator with anadvanced warning of service requirements.

It will be appreciated that sensor 50 may be configured for weardetection and prefabricated within a component for use within combustionturbine 10 either alone or in combination with a means for transmitting52 in accordance with aspects of the present invention. In this respect,the signals extracted for detection of wear may be conducted viaconnectors 52 to transmitter 54, which may transmit the signals viawireless telemetry to a transceiver 56 and subsequently system 30.

Embodiments of the present invention allow for monitoring and controlsystem 30 to collect and store historical data with respect to acomponent's wear and correlating the component's wear with the operatingconditions of combustion turbine 10 responsible for producing the wear.This may be accomplished by continuously interrogating turbine 16conditions, for example, by the deposition of piezoelectric devicesand/or other sensors 50 configured for providing a continuous datastream indicative of the loading conditions, vibration frequency,resonance and other operating parameters experienced by variouscomponents within turbine 16. This data may be correlated to dataindicative of a component's wear and used for predictive maintenance orother corrective actions.

FIG. 7 illustrates another exemplary embodiment of a sensor 50 that maybe configured as an exemplary heat flux sensor 61 for measuring heatflux across a barrier coating such as a thermal barrier coating (TBC)60, which may be yttrium-stabilized zirconium. Using known techniques,thermal barrier coating 60 may be deposited on a bond coat 62, which maybe deposited on a substrate 64. Substrate 64 may be various componentssuch as a superalloy suitable for use in turbine 16, and in anembodiment may a blade 18. The heat flux may be used to obtain thesurface temperature of substrate 64 without having to expose the surfaceof substrate 64 to the surface temperature experienced by the uppersurface of thermal barrier coating 60.

Thermocouples 66 may comprise a material having a coefficient of thermalexpansion that substantially matches that of the material within whichthey are deposited, such as thermal barrier coating 60. In anembodiment, a plurality of temperature sensors, such as K-typethermocouples 66 may be embedded within a thermal barrier coating 60with thermocouples 66 located vertically over each other as shown inFIG. 6. In an embodiment, thermocouples 66 may include a NiCr/NiAlthermocouple junction. Alternate embodiments allow for thermocouples 66to be fabricated of other materials such as Pt and Pt—Rh for hightemperature applications such as those within turbine 16.

Heat flux sensor 61 may be formed in different geometries to achieve adesired signal-to-noise ratio. Each thermocouple 66 may be approximately25 microns thick but this thickness may vary depending on theapplication. Because the thermal barrier coating 60 may be several timesas thick as thermocouples 66 they will not significantly alter theprofile or performance of thermal barrier coating 60. Embodiments allowfor post deposition laser micromachining to achieve a desired junctiondensity.

As heat flows vertically into or out of thermal barrier coating 60, eachthermocouple 66 will record a different temperature measurement. Bymeasuring the temperature differences and knowing the thickness andthermal conductivity of thermal barrier coating 60, the heat flux can beobtained. Thermocouples 66 may be connected with a means fortransmitting 52 as described herein so that the respective temperaturemeasurements taken by each thermocouple 66 may be wirelessly transmittedto monitoring and control system 30.

FIGS. 8 and 9 illustrate an exemplary embodiment of a sensor 50 that maybe configured as an exemplary sensor 68 configured for detecting and/ormeasuring strain or a crack within a location of interest such assubstrate 70. For example, substrate 70 may be a location of interest ofa area of a blade 18, or it may be other locations of interest within orat the surface of thermal barrier coating 60 or bond coat 62. It will beappreciated that sensor 68 configured in this manner may be used innumerous places throughout combustion turbine 10. The sensors describedin FIGS. 8 and 9 describe the utilization of the change in resistance toresult in a strain output. Other embodiments of strain gauges could alsoinclude capacitive changes to determine the local strain values.

In this respect, critical engineering components, such as blades 18, 19and vanes 22, 23 are nearly universally subjected to some form ofmechanical and/or thermo-mechanical cyclic loading. Aspects of theinvention allow for the assessment of component service life by theintermittent or continuous, in-situ measurement of applied strains andcrack detection with respect to that component. This may be accomplishedby the placement of embedded strain gages and crack sensors 68 invarious locations within combustion turbine 10. Sensors 50 configured asa strain gauge 68 may be formed using a NiCr material for use in lowertemperature applications, such as in compressor 12 of combustion turbine10.

Sensors 68 may be used as crack sensors by placing them at locations orpoints where cracks are known or likely to appear. A crack sensor gauge68 may be optimized for size, crack propagation, and crack extentthrough appropriate choice of gauge 68 parameters. Such parameters mayinclude the footprint of gauge 68, spacing of fingers 72, andorientation of fingers 72 with respect to the direction of a predictedcrack propagation. Crack formation in substrate 70 gives rise to alarge, abrupt change in the strain gauge response, and may be detectedby continuously monitoring the sensor 68 output for abrupt signalchanges using signal processing techniques. Data indicative of thesignal change may be conducted via a means for transmitting 54 to atransceiver 56 and subsequently transmitted to monitoring and controlsystem 30 via wireless telemetry.

In an exemplary embodiment, a strain gauge sensor 68 may be bonded to ordeposited on a surface of a compressor blade 19 and positioned so thatbending stress on blade 19 varies the output signal from sensor 68.Connector 52, which may be wire leads, are routed to a transmitter 54located on a rotating collar internal to compressor 12. Transmitter 54may have an onboard bridge completion and provide a regulated voltage tosensor 68. As the output signal from sensor 68 varies an RF signal fromtransmitter 54 varies proportionally. The RF signal may be transmittedto a transceiver 56, which receives the RF signal and converts it into avoltage signal proportional to the strain detected by sensor 68. The RFsignal may be transmitted to system 30. An exemplary transmitter 54 maypick up changes in strain from about 30 Hz to about 30 KHz.

Embodiments of the invention allow for using crack sensors 68 to monitorcrack growth during operation of combustion turbine 10 and verify designmodels by varying component operating parameters until cracks aredetected with the crack sensors 68. The design models will be calculatedfor the same operating parameters to see if they successfully predictcrack growth and formation, and will be modified accordingly.

Monitoring and control system 30 may collect and store data indicativeof strain and crack measurements from numerous components in criticallocations within combustion turbine 10, such as blades 18, for example.Such data may be analyzed over time to develop a strain history for eachcomponent. A component's strain history may include the magnitude andorientation of strains, and the occurrence of overloads under cyclicloading. An appraisal of fatigue damage may be developed and used forpredictive maintenance.

Embodiments of the present invention allow for deploying a plurality ofsensors 50 throughout combustion turbine 10 by either surface mountingthem to components or embedding them within respective component barriercoatings to collect specific component condition data and transmit thatdata using wireless telemetry to monitoring and control system 30. Thisapproach is advantageous in that it allows for the replacement, repairand maintenance decision-making processes to be based on the conditionof specific components during operation of combustion turbine 10.

In this respect, specific component condition data may be received byantenna 32 and receiver 33 then stored in database 36 by CPU 34.Embodiments allow for specific component condition data to be collectedand presented to an operator in real time via display 38. This allowsfor an operator to make instantaneous decisions regarding the operationof combustion turbine 10 in response to the condition of a specificcomponent or components.

Historical data may be compiled and analyzed with respect to eachcomponent for making repair, replacement or maintenance decisions withrespect to that component. Operating conditions and specific componentsof combustion turbine 12 may be monitored sets of conditions may beisolated that are indicative of a component or components needing to berepaired or replaced, or of corrective action to be taken with respectto operation of the gas turbine. These aspects allow for significantimprovement in predictive maintenance schedules.

FIG. 10 is a partial perspective illustration of a component 110 formedof a substrate material 112 having a barrier coating such as a layer ofthermal barrier coating 114 disposed on one surface 116. The component110 may be part of a gas turbine engine 10 of FIG. 1, for example, orany other machine wherein a base material must be protected from anexternal environment by a layer of a barrier material. In an embodiment,component 110 may be an airfoil member, such as a turbine blade 18disposed in the hot gas flow path of a engine 10 with an oxide ornon-oxide ceramic TBC 14 such as mullite, silicon carbide or azirconium-based ceramic overlying a superalloy substrate material 112.

Component 110 may alternatively be fabricated from a ceramic matrixcomposite (CMC) substrate coated with an environmental barrier coating(EBC) or a thermal barrier coating (TBC). Because the integrity of thecoating 114 is critical to the overall integrity of the component 110,it is useful to obtain operating parameter information that directlyaffects the performance of the coating 114. Such information is obtainedby embedding a sensor, such as a sensor 50 below the exposed surface 118of the TBC 114. The sensor is not visible in FIG. 10 but may be locatedbelow surface 118 in the sensing location indicated generally by numeral120.

The sensor may be one that provides a signal indicative of temperature,strain, crack initiation, chemical changes, vibration, acceleration,pressure or other parameters of interest. These sensors themselves couldbe multi-layered containing a combination of electrodes and thefunctional body. For example, pressure may be measured using a thermallysprayed piezoelectric load cell and acceleration (vibration) may bemeasured using a thermally sprayed piezoelectric or piezoresistiveaccelerometer embedded within coating 118.

Conductors 122 may be located below surface 118 and route the signalproduced by the sensor away from sensing location 120 to a terminationlocation, which may be a connection location indicated generally bynumeral 224 where they can conveniently exit the component 110.Conductors 122 may function similarly to connectors 52 for routing asignal from a sensor, such as a sensor 50 to a transmitter 54 fortransmission to system 30 via wireless telemetry. The sensor andconductors 122 may be insulated from the surrounding environment byinsulating layer 126.

FIG. 11 is a partial cross-sectional view of another component 130having a substrate material 132 covered by a barrier coating such as alayer of a thermal barrier coating material 134 for use in a very hightemperature environment. As is well known in the art of TBC coatings, abond coat 136 such as an MCrAlY material may be deposited on thesubstrate 132 prior to the application of the TBC material 134 toimprove the adherence of the coating 134 to the substrate 132.

Component 130 may be instrumented by a plurality of sensors, such assensors 50 embedded at a plurality of depths below a surface 138 of theTBC material 134 that is exposed to the external environment. A firstsensor 140 is deposited in a relatively shallow trench 142. Trench 142may be lined with an electrically insulating coating 144 such asaluminum oxide to prevent the grounding of sensor 140 to the TBCmaterial 134. Sensor 140 may take any form known in the art, for examplea thermocouple formed by a bimetallic thermocouple junction or othersensors described herein. The surface location of sensor 140 suggeststhat it may be useful for sensing a parameter related to the externalenvironment, such as temperature or a chemical parameter.

FIG. 12 illustrates the steps of a process 150 that may be used duringthe manufacturing of the component 130 of FIG. 11. In step 152, a layerof thermal barrier coating material 134 may be deposited onto asubstrate 132. After step 152, the component is completed in its normaloperating shape as it may be used without embedded instrumentation. Oneskilled in the art may appreciate, therefore, that the process 150 maybe applied to newly fabricated components or it may be back fit to anexisting component that is in inventory or that has been in service.

In step 154, a trench 142 may be formed in a surface 138 of thecomponent 130. Trench 142 may be formed to any desired shape by anyknown method, such as by laser engraving trench 142 to have a generallyrectangular cross-section with a predetermined width and depth.Variables for such a laser engraving process include spot size, powerlevel, energy density, pulse frequency, and scan speed. These variablestogether affect the trench width, depth, material removal rate and thecost of manufacturing. Trench 142 may have a constant cross-sectionalsize and shape along its entire length, or it may vary in size and/orshape from one region to another. For example, in the component 110 ofFIG. 10, a trench formed in the sensing location 120 may have differentdimensions than the trench extending from the sensing location 120 tothe connecting location 124, since the sensor and the conductors 122 mayhave different geometries. The trench 142 may also be inclined to thesurface, i.e. varying in depth along its length, which in someapplications may provide improved mechanical integrity within thecomponent.

After trench 142 is formed at step 154, an insulating coating 144 may beapplied to the surfaces of the trench 142 at step 56 in order to provideelectrical isolation between sensor 140 and TBC material 134. Insulatingcoating 144 may be deposited by any known method such as chemical vapordeposition (CVD) to a thickness sufficient to achieve a desired level ofelectrical isolation. Once the trench 142 is formed at step 154 andinsulated at step 156, the sensor 140 may be formed by depositing theappropriate material or materials into trench 142 at step 158. Any knownmaterial deposition process providing the desired material propertiesmay be used. Such processes are common in the fields of rapidprototyping, thin and thick film deposition, and thermal spraying, andinclude, for example, chemical vapor deposition, plasma spray,micro-plasma spray, cold spray, electroplating, electrophoreticdeposition, HVOF, sputtering, CCVD, sol-gel and selective laser melting.Processes typically used for the fabrication of multi-layer thick filmcapacitors may also be used, such as the application of pastes and tapesof the desired materials.

After the deposition of material, a heat input may be used to sinter thematerial, thereby increasing the mechanical integrity of the sensor.This can be done either by heating using a flame, plasma, furnaceannealing or localized laser energy application. In the selective lasermelting (SLM) process, powdered material having a predeterminedchemistry may be deposited into the trench and melted with the energy ofa laser beam to form the respective portion of the sensor 140 of FIG. 11or the interconnecting conductors 122 of FIG. 10. For example, to form athermocouple, platinum powder may be deposited into one portion oftrench 142 and solidified by a SLM process. Platinum-rhodium powder maythen be deposited into a second portion of trench 142, either along thetrench length or as a second vertical layer, and solidified by a SLMprocess to contact the platinum material to form the thermocouplejunction.

Note that the geometry of trench 142 may have a direct effect on thegeometry of the sensor 140. Accordingly, it is possible to affect theoperating parameters of sensor 140 or interconnecting conductors 122 bycontrolling the dimensions of the respective trench 142. For example,the resistance of a conducting line formed within a trench will beaffected by the width of the trench. The laser engraving process of step154 may be closely controlled to achieve a desired trench geometry.Certain commercially available processes for depositing a conductor ontoa flat surface by thermal spraying may not produce the fine featuresthat may be necessary for sensors and conductive lines. Such processesmay rely on a subsequent material ablation process to achieve a desiredgeometry. Because trench 142 provides control of the width of thefeature, no such trimming step is needed in the process 150 of FIG. 12.

FIG. 11 also illustrates a second trench 160 formed in the TBC material134 to a second depth that is farther below surface 138 than trench 142.By forming a plurality of trenches 142, 160 at a plurality of depthsbelow surface 138, it is possible to place sensors, such as sensors 50at more than one depth within the component 130, thereby furtheraugmenting the available operating parameter data. In the embodiment ofFIG. 11, trench 160 contains two vertically stacked conducting layers162, 164 separated by an insulating layer 166. The conducting layers162, 164 may form two portions of a sensor, or two conducting lines forconnecting a sensor to a connecting location. 1As illustrated in FIG.12, the two conducting layers 162, 164 may be formed by first depositingconducting layer 162 at step 158, and then depositing an insulatinglayer 166 at step 168 using any desired deposition technique, such asCVD.

Steps 158, 168 are then repeated to deposit conducting layer 164 andinsulating layer 174. The width of these layers is controlled by thewidth of trench 160 and the thickness of these layers may be controlledas they are deposited to achieve predetermined performancecharacteristics. For example, the thickness of insulating material 166will affect the impedance between the two conducting layers 162, 164.Conducting layer 164 is then isolated from the external environment bybackfilling the trench 160 with a barrier material such as thermallyinsulating material 170 at step 172. Insulating material 170 may be thesame material as TBC material 134 or a different material having desiredcharacteristics. Insulating material 170 may be deposited by any knowndeposition technique, including CVD, thermal spraying, selective lasermelting, or selective laser sintering. Selective laser melting andselective laser sintering processes are known in the art, as exemplifiedby Chapters 6 and 7 of “Laser-induced Materials and Processes For RapidPrototyping” by L. Lu, J. Y. H. Fuh, and Y. S. Wong, published by KluwerAcademic Publishers.

Additional sensors 176, 178 may be disposed at preselected depths withincomponent 130 by forming respective trenches 180, 182 to appropriatedepths. Trenches 180, 182 may be backfilled with insulating material 170to the level of surface 138 at step 172. Planarization of surface 138may be performed at step 184, if necessary, such as when surface 138forms part of an airfoil. By forming a trench to a desired depth, asensor may be embedded to within the TBC material layer 134, to withinthe bond coat material layer 136, to within the substrate material 132,or to a depth of an interface between any two of these layers.

Thus, it is possible to develop actual operating parameter data across adepth of a component or across the depth of the thermal barrier coating.Such data may be useful for confirming design assumptions and forupdating computerized models, and it may also be useful as an indicatorof damage or degradation of a TBC coating. For example, a sensor 178embedded below the TBC material 134 may produce a signal indicating asignificant temperature rise in the event of cracking or spalling of thelayer of TBC material 134. Alternatively, the detection of apredetermined level of vanadium, sodium or sulfur deposits by anembedded sensor 176 may announce conditions that would give rise tospalling and failure of the TBC coating 134 if the component were toremain in service for an extended period. This process facilitates theplacement of sensors at any location on a fully assembled and coatedpart. Electrochemical sensors on the component surface can play animportant role in determining the nature and effect of corrosionproducts present in the surrounding environment.

Embodiments of sensors may be used in various places within combustionturbine 10 as load cells and accelerometers. FIG. 13 illustrates a planview of a portion of turbine 16 that will be understood by those skilledin the art. A casing 200 of turbine 16 may have a forward isolation ring202 and an aft isolation ring 204 slip fit within respective groovesformed within casing 200. A ring segment 210 may be slip fit withinrespective grooves formed within isolation rings 202, 204. Ring segment210 may include forward hooks 212 and aft hooks 214 that fitrespectively within forward groove 216 and aft groove 218 of isolationrings 202, 204. An anti-rotation locking mechanism 220 may be adjustablymounted to casing 200 for preventing circumferential motion of ringsegment 210 within grooves 216, 218.

FIG. 13 also illustrates a portion of a turbine blade such as a blade 18that is attached to a rotor disk (not shown) as recognized by thoseskilled in the art. A plurality of blades 18 are typically attached tothe rotor disk and rotate as a working gas flows through turbine 12. Acooling flow channel 222 may be formed between ring segment 210 andcasing 200 through which air may flow to cool components outside the hotgas path. Air flowing through cooling flow channel 222 may be at ahigher pressure than air pressure within the hot gas path, which helpsto ensure that the cooling air flows out of and not into the hot gaspath. This pressure differential may cause one or more ring segments 210to be biased radially inwardly toward blade 18 during operation.

FIG. 14 illustrates an exemplary ring segment 210 removed from isolationrings 202, 204, which may have a coating such as a TBC 26 applied on aninterior surface. TBC 26 insulates ring segment 210 from hightemperatures and helps to minimize the amount of air flowing throughchannel 222 required to cool components outside the hot gas path. Theinterior surface is exposed to blade 18 during operation of turbine 16.It has been determined that during operation of combustion turbine 10the interface between hooks 212 of ring segment 210 may wear against anadjoining portion of groove 216 of isolation ring 202.

As shown in FIG. 14, wear areas 226 may be formed in hooks 212 due totheir rubbing against surfaces created by groove 216. Similar wear areasmay occur on other components. This rubbing or impinging is due tovibration during operation of combustion turbine 10 and ring segment 210being urged radially inwardly toward blade 18 because of the airpressure differential between cooling flow channel 222 and the hot gaspath. As ring segment 210 is urged inwardly TBC 26 may be gradually wornaway such as in surface area 228 due to the tip of blade 18 rubbingagainst the coating. Damage to the tip of turbine blade 18 may alsoresult. This wearing away on one or more ring segments 210 or damage toblade 18 may lead to inefficient operation of combustion turbine 10, anincrease in demand for cooling air, or cracking in or critical failureof ring segment 210 or turbine blade 18.

When ring segment 210 is initially slip fit within isolation rings 202,204 via hooks 212, 214 the interface or contact surfaces between hooks212, 213 and surfaces defined by respective grooves 216, 218 form closetolerances. When combustion turbine 10 is in operation vibration causesthe contact surfaces to rub against one another, which may lead to wearareas 226 and eventually to wear in surface area 228 of TBC 26 on ringsegment 210. It would be advantageous to detect and monitor thepressures being exerted in these contact areas to measure or predictwear there between and prevent an unacceptable wearing of TBC 26.Traditional sensors are not suited for this application due primarily totheir size and poor reliability due to their attachment method.

FIG. 15 illustrates an exemplary embodiment of a sensor 50, such as aload cell 229 that may be deposited in accordance with aspects of theinvention. The inventors of the present invention have determined thatthe direct write apparatus and process may be uniquely applied todeposit sensors in areas that have previously been inaccessible usingtraditional sensors. In this respect, a sensor 50 may be deposited asload cell 229 comprising a piezoelectric material 230 using the directwrite apparatus or process. Conductive material may be deposited to formconductive leads 232, 236, which may extend to termination point forconnection with a wireless amplifier and signal conditioner for load orvibration measurement. In an embodiment, a first or bottom insulatinglayer (not shown) may be deposited on a substrate 234 to insulateconductive lead 232. Substrate 234 may be various components ofcombustion turbine 10 including portions of one or more hooks 212.

Piezoelectric material 230 may be deposited on conductive lead 232 withconductive lead 236 deposited on top of material 230. An insulatinglayer (not shown) may be deposited over conductive lead 236 with anotherprotective layer deposited on top of the insulating layer such as a wearresistant coating, TBC or other material to build the surface to adesired dimension. Conductive leads 232, 236 may be connected with aconventional or wireless amplifier and data signals extracted from loadcell 229 may be transmitted to control system 30 via transmitters suchas transmitters 54. It will be appreciated that sensors 50 formed as aload cell 229 may be deposited in various configurations, orientationsand locations depending on a particular application. For example, loadcells 229 may be modified and directionally oriented for detecting andmeasuring bending and shear forces experienced at a point of interest.

FIG. 16 illustrates an exemplary embodiment of a sensor 50, such as anaccelerometer 250 that may be deposited using the direct write apparatusand process in accordance with aspects of the invention. A sensor 50 maybe deposited as an accelerometer 250 comprising a piezoelectric material230 deposited on substrate 251 using the direct write method andapparatus. Substrate 251 may be various components of combustion turbine10 including portions of one or more hooks 212. A central inertial mass252 of suitable material may be deposited within piezoelectric material230. Mass 252 has a sufficient density for creating appreciable shearforces in cooperation with piezoelectric material 230. Conductivematerial may be deposited to form conductive leads 254, 256. Insulatinglayers (not shown) may be deposited to insulate conductive leads 254,256 from surrounding material.

Conductive leads 254, 256 may be extend to a termination location forconnection with a conventional or wireless amplifier and data signalsextracted from accelerometer 250 may be transmitted to control system 30via transmitters such as transmitters 54. It will be appreciated thatsensors 50 formed as an accelerometer 250 may be deposited in variousconfigurations, orientations and locations depending on a particularapplication.

FIG. 17 illustrates a cross section of an exemplary load cell 229deposited on substrate 234. An insulating layer 260 may be deposited onsubstrate 234 with a first conductive layer or lead 262 deposited onlayer 260. Piezoelectric material 230 may be deposited on layer 260 witha second conductive layer or lead 264 deposited on piezoelectricmaterial 230. An insulating layer 266 may be deposited over layers 260,262, 230 and 264 to encapsulate the sensor and ensure first and secondconductive leads 262, 264 and insulated from each other. A top layer 268such as a wear resistant coating or TBC may be deposited on or overinsulating layer 266. This coating may vary in thickness depending onthe specific application.

Load cell 229 and accelerometer 250 may be used for detecting andmeasuring vibration or loading at points of interest within combustionturbine 10. In exemplary embodiments, they may be deposited directlyonto the surface of a component or within a recess formed within acomponent. Voltage and frequency response may be measured foridentifying wear drivers and responses of material and combustionturbine 10 operations to the wear. Coatings may be deposited there oversuch as a wear resistant coating using a thermal spray process.Embodiments of load cell 229 and accelerometer 250 may be depositedwithin trenches formed in barrier coatings as disclosed in U.S. Pat. No.6,838,157. Embodiments of load cell 229 and accelerometer 250 may havepiezoelectric material 230 deposited directly onto a surface of aconductive substrate where the conductive substrate functions as one ofthe conductive leads forming a respective sensor 50.

Embodiments of the invention allow for areas of components of combustionturbine 10 to be repaired in the field. For example, as shown in FIGS.13 and 14, wear areas 226 on hooks 212 of ring segment 210 may be causedby hooks 212 rubbing against surfaces of isolation ring 202 formed bygroove 216. Such wear areas 226 may be repaired by removing ring segment210 from isolation rings 202, 204 and depositing a coating, such as awear resistant coating over the wear areas 226. This depositing buildsthe worn area of a hook 212 back up to its original dimension.

In an embodiment of the invention, an exemplary load cell 229 and/oraccelerometer 250 may be deposited as part of the wear resistant coatingdeposited over a wear area 226. In this respect, the load cell 229 maybe deposited within the wear resistant coating precisely at a locationof interest. The location of interest may be the contact surfacesbetween a hook 212 and a respective surface of isolation ring 202against which hook 212 rubs during operation of combustion turbine 10.Instrumenting ring segment 210 with one or more load cells 229, forexample, at these areas of interest is advantageous because it allowsfor data to be extracted with respect to loads, pressure and relativemovement realized at the contact surfaces.

Exemplary embodiments of load cells 229 and/or accelerometers 250 may bedeposited within original components for use in combustion turbine 10 orexisting components within combustion turbine 10 may be retrofit withembodiments of these sensors. In certain situations an existing or to beapplied coating, such as a wear resistant coating may be relativelythin, i.e., about 3 mils. In this situation, load cell 229 and/oraccelerometer 250 may be deposited within a recess or trench formedwithin the surface of the component or barrier coating. A wear resistantcoating may be re-deposited or deposited over load cell 229 and/oraccelerometer 250 so the wear resistant coating is at a desiredthickness.

While the preferred embodiments of the present invention have been shownand described herein, it will be obvious that such embodiments areprovided by way of example only. Numerous variations, changes andsubstitutions will occur to those of skill in the art without departingfrom the invention herein. Accordingly, it is intended that theinvention be limited only by the spirit and scope of the appendedclaims.

1. A method of instrumenting a first component for use in a combustionturbine engine, the first component comprising a surface contacted by asecond component during operation of the combustion turbine engine, themethod comprising: depositing an insulating layer on the surface of thefirst component; depositing a first conductive lead on the insulatinglayer; depositing a piezo-material in electrical communication with thefirst conductive lead; and depositing a second conductive lead inelectrical communication with the piezo-material and insulated from thefirst conductive lead to form a sensor for detecting pressure exerted onthe surface of the first component during operation of the combustionturbine engine.
 2. The method of claim 1, the steps of depositingcomprising using a direct write thermal spray process.
 3. The method ofclaim 1 further comprising forming the sensor in a worn surface of thecomponent.
 4. The method of claim 3 further comprising depositing a wearresistant coating over the sensor.
 5. The method of claim 1 furthercomprising forming the sensor as a load cell.
 6. The method of claim 1further comprising depositing a central mass to form the sensor as anaccelerometer.
 7. The method of claim 1 further comprising: forming atleast one trench to a predetermined depth in a layer of barrier coatingmaterial deposited on the surface of the first component; and formingthe sensor within the at least one trench.
 8. The method of claim 7further comprising: refilling the at least one trench with a protectivecoating.
 9. A component comprising: an insulating layer deposited on asurface of the component; a first conductive lead deposited on theinsulating layer; a piezo-material deposited on the first conductivelead; and a second conductive lead deposited on the piezo-material toform a sensor for detecting pressure exerted on the surface of thecomponent.
 10. The component of claim 9 further comprising a protectivecoating deposited over the sensor.
 11. The component of claim 9 furthercomprising a central mass deposited within the piezo-material to formthe sensor as an accelerometer.
 12. The component of claim 9 furthercomprising: a wear resistant coating deposited on the surface of thecomponent; and at least one trench formed in the wear resistant coatingwherein the sensor is deposited within the at least one trench.
 13. Thecomponent of claim 12 further comprising a wear resistant coatingdeposited over the sensor.
 14. A component for use in a combustionturbine engine, the component comprising a piezo-material embeddedbeneath a surface of the component, the surface being contacted by asecond component during operation of the combustion turbine engine. 15.The component of claim 14 further comprising a wear resistant materialdefining the surface of the component.
 16. The component of claim 14further comprising a central mass deposited within the piezo-materialforming an accelerometer.
 17. The component of claim 14 furthercomprising: a first conductive lead extending from the piezo-material toa termination location; and a second conductive lead extending from thepiezo-material to the termination location.
 18. The component of claim14 further comprising: a barrier coating material defining the surfaceof the component; and at least one trench formed within the barriercoating material wherein the piezo-material is deposited within the atleast one trench.
 19. The component of claim 18 further comprising: afirst conductive lead deposited within the at least one trench andextending from the piezo-material to a termination location; and asecond conductive lead deposited within the at least one trench andextending from the piezo-material to the termination location whereby aload cell is formed for detecting a load on the surface of the componentduring operation of the combustion turbine engine.
 20. A method ofinstrumenting a component for use in a combustion turbine engine, thecomponent comprising a conductive substrate, the method comprising:depositing a piezo-material on a surface of the conductive substrate;depositing an insulating layer on the conductive substrate to atermination location; and depositing a conductive lead on the insulatinglayer extending from the piezo-material to the termination location. 21.The method of claim 20 wherein the surface is contacted by a secondcomponent during operation of the combustion turbine engine.
 22. Themethod of claim 20 further comprising: forming a recess within thesurface of the conductive substrate; and depositing the piezo-materialin the recess.
 23. The method of claim 22 further comprising depositinga wear resistant coating over the piezo-material.
 24. The method ofclaim 20 wherein the surface is non-planar and the steps of depositingcomprising using a direct write thermal spray process.